Paula Broadwell, the author suspected of carrying on an affair with former CIA director David Petraeus, has been stripped of her military security clearance after a federal probe alleged she was storing classified military material at her home.

"Appropriate actions with regard to this officer's clearance and access have been taken," said Army spokesman George Wright of Broadwell, an Army reservist and West Point graduate.

The inquiry into Broadwell came as Petraeus, one of the country's most decorated generals, was being pressed to appear before congressional committees to answer questions about the Sept. 11 terror attack on the U.S. consulate in Benghazi, Libya. He was being asked to testify nearly a week after he publicly admitted to having an affair and resigning his post at the CIA.

This evening, the House Permanent Select Committee on Intelligence said Petraeus will appear behind closed doors to testify to the committee at 7:30 a.m. Friday.

Petraeus has been reluctant to testify following his resignation as CIA chief, but pressure has been growing in Congress for him to appear.

Petraeus also was being asked to appear before a Senate committee.

"Gen. Petraeus is willing to come before the committee and the details are being worked out," Sen. Diane Feinstein, chairwoman of the Senate Foreign Relations Committee, said today. No date for his testimony has been set.

On the Broadwell matter, a source familiar with the case told ABC News that Broadwell admitted to the FBI she took documents from secure government buildings. The government demanded that they all be given back, and federal agents descended on her North Carolina home on Monday night in pre-arranged visit.

Prosecutors were determining whether to charge Broadwell with a crime and this morning the FBI and military were poring over the material.

The 40-year-old author, who wrote the biography on Gen. Petraeus, "All In," is cooperating with the investigation. The case is complicated by the fact that, as an intelligence officer in the U.S. Military Reserve, Broadwell had security clearance to review the documents.

At a news conference this afternoon, President Obama said there was no evidence that the material contained secrets crucial to the country's national security.

"I have no evidence at this point, from what I've seen, that classified information was disclosed that in any way would have had a negative impact on national security," he said.

The FBI found classified material on a computer voluntarily handed over by Broadwell earlier in the investigation. Prosecutors will now have to determine how important the classified material is before making a final decision on how to proceed. Authorities could decide to seek disciplinary action against her rather than pursue charges.

Senior FBI officials were expected to brief the House and Senate Intelligence Committees today on their handling of the Petraeus investigation. The officials were expected to lay out how the case was developed and argue that there were no politics involved.

The case was so critical that FBI Director Robert Mueller may attend to defend the bureau, ABC News has learned. Members of Congress have been angry that they were not informed about the case before the story was reported by the media, but FBI officials maintained that their guidelines forbade them from discussing ongoing criminal cases.

Investigators are said to have then found emails in Broadwell's inbox that pointed to an intimate affair with Petraeus, who on Friday admitted to an affair and announced his resignation as CIA director.

The FBI also uncovered "potentially inappropriate" emails between Gen. John Allen, the commander of American forces in Afghanistan, and Kelley, according to a senior U.S. defense official who was traveling with Defense Secretary Leon Panetta. The department was reviewing between 20,000 and 30,000 documents connected to the matter, the official said. The email exchanges between Kelley and Allen took place from 2010 to 2012.

Leon Panetta: 'No One Should Leap to Any Conclusions' Regarding Gen. Allen

The U.S. official said the emails were "innocuous" and mostly about upcoming dinner parties and seeing him on TV.

Allen denied he was involved in an affair, a Pentagon official said.

An intermediary for Allen told ABC News that Allen and his wife are friends with Kelley and her husband and most of the emails were sent from Kelley to Allen's wife.

A U.S. official said Allen may have triggered the investigation when he got an anonymous email a few months ago that was traced to Broadwell. The email had a "Kelley Patrol" return address or subject line and painted Kelley as a seductress, which Allen found alarming and mentioned to Kelley in a subsequent email, the official said.

The official described Kelley as a "nice, bored, rich socialite who drops the honorary from her title ... and tells people she is an ambassador. She gets herself in anything related to Centcom and all the senior people and has been for years."

Panetta cautioned that "no one should leap to any conclusions" about allegations against Allen over the investigation.

Panetta said he supports Allen, who has been in command in Kabul, Afghanistan, since July 2011. He took over that summer for Petraeus, who retired from the Army to take over as the head of the CIA.

"He [Allen] certainly has my continued confidence to lead our forces and to continue the fight," Panetta said at a news conference in Perth, Australia, Wednesday.

Panetta declined to explain the nature of Allen's correspondence with Kelley.

Secretary of State Hillary Rodham Clinton, who appeared with Panetta, declined to comment on the Allen case, but insisted the scandal has not harmed the war effort.

"There has been a lot of conversation, as you might expect, but no concern whatsoever being expressed to us because the mission has been set forth and it's being carried out," Clinton said.

Allen has been nominated as the next commander of U.S. European Command and the commander of NATO forces in Europe -- but, despite President Obama's backing, the nomination has been put on hold. The change of command at NATO is currently slated not to take place until March at the earliest.

Allen was supposed to appear before a Senate confirmation hearing this Thursday alongside his designated replacement, Marine Gen. Joseph Dunford. Panetta said that while the matter is being investigated by the Defense Department IG, Allen will remain in his post as commander of the International Security Assistance Force, based in Kabul.